Greenbull is correct on how the one piece world work.
His justice is similar to kaido view on world is might is right , natural jungle law , survival of fitness.
It is like kaido marine version.
Kaido want to enslave wano for his agenda .
‘Greenbull want to enslave wano for World government agenda .
To change greenbull mind in wano is when luffy beat him down to parallel sword ryuma god beat world government guys to keep them off wano and wano become luffy territory.
Doubt talking work on greenbull.
I have gut feeling greenbull is new King and kaido slowly become new katakurI/doflimingo as powercreep went out wack, and big mom is just beating dead horse like Hody jones. But Hody jones as character is better than big mom.